Due to changes in demand, and in more cases inheritance hierarchy, sometimes we only need to change some of the ways the behavior of a parent method ACT1 (ACT1 method has been inherited by some subclasses)  * But we do not want to influence the behavior of the original sub-class, how to solve this problem?

由于需求的变动，在继承层次比较多的情况下，有时候只需要修改父类某个行为的部分方法ACT1(ACT1方法已被多个子类继承)， 但又不希望影响子类的原有行为，如何解决该问题？